1 files changed, 7 insertions, 0 deletions
diff --git a/py/gc.c b/py/gc.c
index 734f5c3648..5196954e2e 100644
--- a/py/gc.c
+++ b/py/gc.c
@@ -320,11 +320,18 @@ void gc_collect_start(void) {
     #endif
     MP_STATE_MEM(gc_stack_overflow) = 0;
     MP_STATE_MEM(gc_sp) = MP_STATE_MEM(gc_stack);
+
     // Trace root pointers.  This relies on the root pointers being organised
     // correctly in the mp_state_ctx structure.  We scan nlr_top, dict_locals,
     // dict_globals, then the root pointer section of mp_state_vm.
     void **ptrs = (void**)(void*)&mp_state_ctx;
     gc_collect_root(ptrs, offsetof(mp_state_ctx_t, vm.qstr_last_chunk) / sizeof(void*));
+
+    #if MICROPY_ENABLE_PYSTACK
+    // Trace root pointers from the Python stack.
+    ptrs = (void**)(void*)MP_STATE_THREAD(pystack_start);
+    gc_collect_root(ptrs, (MP_STATE_THREAD(pystack_cur) - MP_STATE_THREAD(pystack_start)) / sizeof(void*));
+    #endif
 }
 
 void gc_collect_root(void **ptrs, size_t len) {